The present invention relates a digital camera, and more specifically to a shutter and lens apparatus with a stepless focusing function.
A digital camera, one of the important peripherals of multi-media computers with advantages of without using films and developing pictures, has become more and more popular nowadays. Unlike the pictures taken by traditional cameras, the images captured by digital cameras are easy to edit and convenient to process associated with other devices, such as personal computer, printer, and so on. Therefore, digital cameras are widely used in various fields, such as web site designs and data preservation.
In spite of the advantages of digital cameras mentioned above, the image qualities of digital cameras are still need to be improved. For most digital camera, CCD and CMOS sensor chips are frequently used to fabricate digital cameras. Although the CCD sensor chip provides better image qualities, it""s also more expensive than the CMOS sensor chip. Therefore, the CCD sensor chip is often used in mega-pixel level digital cameras, and the COMS sensor chip is widely used in introductory machines, such as 300,000-pixel level digital cameras and 800,000-pixel level digital cameras. Actually, the image qualities produced by introductory digital cameras are far behind the qualities of pictures taken by traditional cameras, and the digital cameras of 2 million pixels could only provide images identical to traditional pictures.
When the number of pixel of digital camera exceeds one million, besides the issue of raising memories, the light leakage, a phenomenon that undesired light leaking from shutter device onto the sensor chip, becomes an important issue to fabricate the digital camera. For example, while photo charges generated by a CCD sensor chip are transferring from a vertical charge couple device (VCCD) to a horizontal charge couple device (HCCD), the light leakage would cause noises to damage output images. Currently, mechanical shutter apparatuses are used to prevent the light leakage, however they are not fast enough to suppress the light leakage of mega-pixel level digital camera. Thus, a novel shutter apparatus is needed to prevent the light from leaking onto the sensor chip.
An object of the invention is to provide a shutter and lens apparatus of digital camera.
Another object of the invention is to suppress the light leakage of digital camera.
Yet another object of the invention is to use solenoid valves to prevent undesired light from leaking into a lens of digital camera.
The shutter and lens apparatus of the invention includes a lens housing with a cavity for receiving a multi-function support. The multi-function support has a lens seat atop, and two solenoid valves attached on its bottom. A lens is partially placed in the lens seat, and partially extruding from a top surface of the multi-function support. A shutter slice with a shutter aperture is pivoted on a shaft of the top surface of multi-function support, and placed in a slot of the lens. Initially, the shutter aperture coincides with the axis of the lens for allowing light to pass through the lens and project on a sensor chip. When the shutter button is pushed, the shutter slice is driven to swing across the slot by a rod attached on one of the solenoid valves, so as to prevent an undesired amount of light from leaking onto the sensor chip. Since the solenoid valve has a high operating frequency, the instant of the shutter slice pass across the slot would be short enough to suppress the light leakage. A diaphragm with two apertures in different radii is pivoted on the shaft the shutter slice mounted on. Similarly, the diaphragm is driven by the solenoid valve to swing in the slot of lens so as to allow an amount of light passing through the lens via the apertures. Since the apertures are in different radii, the amount of the light passing through the lens could be alternated by switching the apertures. The diaphragm and the shutter slice are separately coupled with two rods of solenoid valves thereby being driven simultaneously with the operating frequency of them. In addition, a split sticking through the lens is set between the shutter slice and diaphragm for avoiding interference while the shutter slice and the diaphragm moving.
Three extrusions around the lens seat are projected from a bottom surface of the multi-function support. The three extrusions respectively rest on and move along three inclines, which have the same slopes and altitudes, of a focus adjustment thereby changing altitudes of the lens fitted in the lens seat of multi-function support.
The focus adjustment is constructed with a focus adjusting gear and a lens tube with three inclines atop being set in the center of the focus adjusting gear. The lens tube fits with the lens seat so as to keep the inclines in touch with the extrusions. When the focus adjusting gear turns, the extrusions relatively move along the inclines thereby changing altitudes of the lens. A first decelerating gear and a second decelerating gear are connected between the focus adjusting gear and driving means, such as a stepping motor. Therefore, the driving means could adjust the focus of the lens via the combination of gears. In addition, a micro adjustment including several gears is connected with the focus adjustment for predetermining altitudes of the lens by adjusting the gears, and the gear would be fixed after the predetermination.
The present shutter and lens apparatus further includes a sensor chip base providing a plurality of pillars to connect to the first decelerating gear, second decelerating gear, and micro adjustment. A sensor chip is mounted on the sensor chip base for receiving the light projected through the lens and transforming it into electric output signals. Finally, a housing cover encases the lens, the multi-function support, and a spring atop the multi-function support into the lens housing, in which the spring stressed between the housing cover and the multi-function support provides a force keeping the extrusions in touch with the inclines.